16. It has been found that how close parents are to their children ______ a rather strong influence on the development of the children's character. ( )
A. have B. has
C. having D. had
17. The audience ______ requested to remain seated during the intermission. ( )
A. are B. is
C. were D. be
18. During extremely hot weather, elephants require both mud and water to keep their skin cool ______ they have no sweat glands. ( )
A. and B. so
C. because of D. due to the fact that
19. His score of the final English exam is higher than ______ in his class. ( )
A. anyone's else B. anyone else
C. anyone's else's D. anyone else's
20. He has been staying at home ______ days. ( )
A. these all last few B. these last few all
C. all these last few D. these last all few
